Abstract: Type 2 diabetes (T2DM) and cardiovascular disease (CVD) are important causes of morbidity and mortality in the elderly population in the United States, costing over $104 billion annually to the Medicare system. The average monthly cost for Medicare beneficiaries with T2DM is 2.2 times higher than that for a Medicare beneficiary without T2DM. Costs of CVD for a Medicare beneficiary with T2DM account for 50% of total costs to Medicare from CVD. Because of 1) the high prevalence of T2DM and CVD, 2) their high costs, 3) increasing longevity, and 4) the increasing number of Medicare-eligible individuals, understanding the trajectory of cardiovascular health in persons with diabetes is becoming increasingly important. However, many modern treatment paradigms, including carotid endarterectomy (CE) and carotid artery stenting (CAS), are based on studies performed before the widespread use of high-potency anti-platelet medications, statins, antihypertensive and glucose lowering medications to prevent CVD, and prior to recent smoking prevention and cessation interventions. We propose to develop a detailed model of cardiovascular disease in persons with diabetes, and to use it to update treatment paradigms for CE and CAS in individuals with TIA. Combining the Cardiovascular Health Study (CHS) and Atherosclerotic Risk in Communities (ARIC) data sets, we will develop risk equations for incident TIA and ischemic stroke following TIA in people with T2DM. The risk equations will depend on demographic descriptors, biomarkers, treatment history, and clinical history. We will calibrate and validate the equations to modern standards of care. The final risk equations will be integrated into the Michigan Model for Diabetes, providing a unified model of CVD (TIA, stroke, and heart disease). Using our CVD model, we will perform cost-effectiveness analysis of CE plus modern medical management (MMM) vs CAS plus MMM vs MMM without surgery and we will develop age-specific recommendations for treatment of TIA in older adults based on best-available evidence.